how to fix P0301 code in Volkswagen Golf MK5 (2004-2008)

Solution

1. Preparation

• Tools Required: OBD-II scanner, socket set, torque wrench, compression tester, multimeter, fuel injector cleaner.
• Safety Warnings: Disconnect the battery before working on electrical systems.

2. Replace Spark Plug and Ignition Coil

1. Remove the engine cover if present.
2. Disconnect the electrical connector from the ignition coil on cylinder 1.
3. Unscrew the ignition coil using a socket.
4. Remove the spark plug using a spark plug socket and inspect it for wear (replace if necessary).
5. Install a new spark plug, torquing it to the manufacturer's specification (usually around 20-30 Nm).
6. Install the new ignition coil and reconnect the electrical connector.

3. Inspect and Clean or Replace Fuel Injector

1. Access the fuel injector for cylinder 1 by removing any intake components as necessary.
2. Disconnect the fuel injector electrical connector.
3. Using a multimeter, check for proper voltage and resistance at the injector.
4. Clean the fuel injector with a suitable injector cleaner or replace it if it fails the test.
5. Reinstall the fuel injector and reconnect the electrical connector.

4. Compression Test

1. Remove the spark plug from cylinder 1.
2. Insert the compression tester into the spark plug hole.
3. Crank the engine for several seconds and read the compression value.
4. Compare the reading to manufacturer specifications (usually around 140-200 psi).
5. If compression is low, further investigation into internal engine components (e.g., valves, piston rings) may be required.